Augers are utilized for boring shallow holes through the surface of the earth. The specific design of any individual auger is usually dependent upon the geology of the strata or formation being penetrated. Some augers are provided with an abundance of excavating teeth, while other augers may be provided with a single or dual cutting surface. The number of cutting teeth placed on the flight of an auger determines the rate of penetration, as well as having a drastic influence on the initial cost of the auger.
The number of teeth also determine the maximum bearing pressure an individual tooth can effect upon the formation being penetrated, and the greater the number of teeth, the less the bearing pressure any one tooth can exert upon a particular formation.
In my previously issued U.S. Pats. No. 3,898,895 and No. 3,794,129, there is disclosed a step-type auger having the teeth thereof arranged in a particular pattern so as to achieve greater efficiency during the boring operation. Reference is made to these two issued patents for further background of the present invention, as well as to the art cited therein.
The present invention relates to improvements in augers by the provision of a dual flight which commences in proximity of a pilot bit and presents diametrically opposed leading edges having digging teeth affixed thereto. The teeth are arranged in a particular pattern which greatly enhances the boring efficiency, as well as the rate of penetration, and at the same time, provides for a substantial reduction in cost.